Field of the Invention
The present invention relates to an electronic device.
Background Art
A flip-chip mounting technique is known as a technique of mounting a chip on a mounting board. In the flip-chip mounting technique, bumps which are protrusion-like terminals are formed on a chip surface and the bumps are soldered to pads on the mounting board. By employing this mounting technique, it is possible to reduce the area of an electronic device including a chip or to reduce loss due to inductance of interconnections, compared with a case where terminals are formed on the outer circumference of the chip.
In such a flip-chip mounting technique, it has been proposed that heat-dissipation performance is improved through bumps by using bumps (hereinafter, also referred to as “stripe bumps”) having a cross-sectional area larger than that of a pillar bump and having a substantially elliptical cross-section in addition to general bumps (hereinafter, also referred to as “pillar bumps”) having a substantially circular cross-section (for example, see Patent Document 1).